Method for operating a ground milling machine, ground milling machine with a mobile component and mobile component for a ground milling machine

ABSTRACT

Method for operating a ground milling machine, in particular a ground stabilizer and/or a recycler; to a ground milling machine, in particular a ground stabilizer and/or recycler, with a mobile unit, in particular for carrying out the method; and to a mobile unit for a ground milling machine. The basic idea of the invention is to transmit suggested values for dosing and/or process parameters via the mobile unit to the ground milling machine during the working operation in progress.

FIELD

The invention relates to a method for operating a ground milling machine, a ground milling machine with a mobile unit, and a mobile unit for a ground milling machine.

BACKGROUND

So-called ground milling machines are frequently used in particular in road and pathway construction. Such a ground milling machine is described, e.g., in DE 102010035129 A1. Examples of such machines include so-called cold milling machines for milling off road and ground surfaces, (ground) stabilizers for stabilizing unstable ground, and recyclers for restoring road pavements in need of repair. These ground milling machines generally comprise injection devices, e.g. in order to reduce the creation of dust during the working process and/or to add a fluid, in particular water, bitumen or foamed bitumen, to the ground material to be processed in order to obtain desired ground properties. The essential implement of such ground milling machines is in particular a milling drum or mixing rotor, which is a drum-like working implement that rotates horizontally and transversely to the working direction and which has a plurality of ground processing tools, such as, e.g., milling chisels, mixing devices, etc., arranged on its external surface. Ground stabilizers are accordingly used in particular for mixing binders into the substrate. An example of a typical binder is lime. So-called recyclers are used for recycling the ground substrate. Frequently, such machines are able to dispense and mix bitumen or foamed bitumen into the substrate. In some cases, both machine types are further capable of dispensing water in a dosed manner and mixing it into the substrate. A dosing system by means of which suitable fluids can be dispensed by the ground milling machine for the purpose of incorporation in the substrate is also described in DE102010035129 A1.

Such a ground milling machine is usually controlled from an operator's cab. From this operator's cab, the driver of the ground milling machine can, e.g., set driving parameters. Driving parameters denote parameters that relate to the movement of the ground milling machine. These are in particular the direction of travel (forward, backward, right, left) and the traveling speed. Moreover, the driver can generally influence process parameters. Process parameters in this context primarily indicate operating parameters of the milling drum, in particular with regard to its milling depth, its transverse inclination (i.e. the inclination of the rotation axis relative to the ground surface) and the rotational speed of the milling drum. The operation of the ground milling machine is further decisively influenced by the dosing of the fluids added to the ground, in particular water and/or bitumen and/or foamed bitumen. The dosage is influenced by the setting of dosing parameters, such as in particular the specification of the amount of the fluid to be discharged, e.g. in relation to a volume of the substrate material, the distance to be travelled, etc., and/or by the control of discharge valves, as described, e.g., in DE 102010035129 A1 and DE 102010013982 A1. Dosing parameters here thus refer to those variables by means of which the dosage of the fluid added to the substrate is controlled, in particular with regard to its type and/or amount.

An optimal adjustment of the amount of dispensed fluid to the prevailing ground conditions is essential for the result of the operation, in particular in the case of ground stabilization and/or recycling processes. According to current standard practice, in particular certain dosing and/or process parameters are set by the driver at the beginning of a milling operation and kept constant for the duration of the operation. It is possible here for the driver of the ground milling machine to interrupt the operation upon completion of a defined working interval and inspect the result. To this end, he usually has to get off the machine to examine the processed ground. Then, he can perform adjustments from the operator's cab in order to improve the final result. However, in particular in cases when, for example, inhomogeneous grounds are processed and/or weather conditions are unfavorable, such as in the case of wind and rain, the results obtained from the operation are not ideal as the dosing of the fluids then occurs in a very imprecise manner.

SUMMARY

In view of this situation, it is the object of the invention to provide a possibility for the improvement of the operation of a ground milling machine in order to obtain a better working result.

The basic idea of the invention is, first, to relieve the driver of the burden of monitoring the ground milling process and, second, to enable him to react to the specific working conditions, in particular ground conditions, in a more effective fashion. Essential here is the use of a mobile unit in accordance with the invention. The latter can be used by a person outside the ground milling machine (referred to as the process expert in the following) to communicate with the driver in the operator's cab of the ground milling machine and to suggest the adjustment of dosing and/or process parameters (specification of suggested values) after an inspection of the substrate, in particular the processed ground area behind the ground milling machine in the working direction, by the process expert. For one thing, this obviates the need for the driver of the ground milling machine to monitor the working result so that he can continue the operation without interruption, while, moreover, an improved result can simultaneously be obtained as it is possible to react more quickly, e.g., to inhomogeneities in the ground.

Specifically, the method according to the invention comprises the following steps: A) Conducting a milling operation on the substrate by setting driving, dosing and/or process parameters, in particular by the driver of the ground milling machine located in the operator's cab. The ground milling machine is thus in working operation and is controlled by the driver inside the operator's cab by means of corresponding operating settings. In particular during this operation, step B) according to the invention involves a parallel examination of the result of the operation and/or the area in front of the ground milling machine in the working direction by the process expert. If he is of the opinion that the adjustment of at least one dosing and/or process parameter is expedient or required, at least one suggested value for at least one dosing and/or process parameter is entered by the process expert via a mobile unit. This can specifically relate to, e.g., decreasing or increasing the fluid discharge, altering the milling depth and/or the rotational speed of the milling drum and/or the lateral inclination of the milling drum, or altering the position of a mixing flap, as described, e.g., in WO 2012/062456 A1. Once the suggested value is entered, it is sent in step C) to the ground milling machine, in particular during the milling operation. The suggested value formulated by the process expert is thus transmitted via the mobile unit to the ground milling machine. This preferably occurs via a wireless data connection. In step D), the at least one suggested value is now displayed in the ground milling machine by means of a display device in the operator's cab of the ground milling machine. A first essential aspect here is thus that the sending of the suggested value does not necessarily result directly in the corresponding implementation of the suggested dosing and/or process parameter but initially “merely” in a display of said suggested value to the driver of the ground milling machine. To this end, a suitable display device is provided in the operator's cab. The display device can be, e.g., an already existing display or a discrete display device provided exclusively for displaying the suggested values. In this case the driver of the ground milling machine thus remains in control of the process and initially only receives information from the process expert via the mobile unit about a possible alteration of the at least one dosing and/or process parameter. It is now ultimately the decision of the driver of the ground milling machine whether or not the suggestion made by the process expert should be implemented. Accordingly, step E) involves an acceptance of the at least one suggested value or a rejection of the at least one suggested value. For example, the rejection can be actively triggered by means of the entry of a corresponding rejection command by the driver. Additionally or alternatively, it is also possible that the suggested value is rejected automatically if the driver of the ground milling machine does not accept it in time (timer function). If the driver accepts the suggested value, step F) finally involves sending, by means of a machine control unit, a corresponding control command for the alteration of an actual value of the at least one dosing and/or process parameter to the at least one accepted suggested value of the at least one dosing and/or process parameter. This occurs through the control of corresponding positioning elements such as valves, orifice plates, pumps, hydraulic cylinders, etc, by the machine control unit. Alternatively, acceptance can also occur automatically after a predetermined time period has elapsed. Additionally or alternatively, it is possible according to the invention that acceptance occurs by means of a specific entry by the driver of the ground milling machine, e.g., by actuation of a suitable input means such as a switch, etc. The machine control unit then uses the value proposed by the process expert and alters the current value of the corresponding dosing and/or process parameter to the at least one accepted suggested value by emitting a suitable control command A sensor system by means of which the actual values of the dosing and/or process parameters are respectively detected is further provided in a known manner for this purpose.

Overall, a considerably improved work result of a generic ground milling machine is achieved with the method according to the invention since, e.g., changes in the properties of the substrate material can be optimized by means of an adjustment of the dosing and/or process parameters during the working operation. This is achieved without placing an additional burdening on the driver of the ground milling machine, since the process expert examines the work result and develops adjustment suggestions independently of the driver of the ground milling machine. By using the mobile unit, the findings of the process expert can be transmitted in a prompt and reliable manner to the driver of the ground milling machine, who, however, remains ultimately responsible for the operation of the ground milling machine, which facilitates a safe operation of the ground milling machine.

In principle, it is possible to enter relative suggested values for dosing and/or process parameters via the mobile unit, e.g., in the sense of “increase” or “decrease”. In this case, it is not necessary for the process expert to have knowledge of an actual value of the dosing and/or process parameter. However, the present optimization process is realized even more precisely if at least one actual value of at least one driving and/or dosing and/or process parameter is additionally displayed on the mobile unit. Based on the displayed actual value, the process expert can then make precise proposals via the mobile unit, in particular also in the form of absolute suggested values, e.g. in the form of an indication of specific numbers. A prerequisite of this embodiment is that the ground milling machine can communicate bidirectionally with the mobile unit, for the transmission of actual values detected at the ground milling machine to the mobile unit as well as for the transmission of the suggested values from the mobile unit to the ground milling machine.

In principle, it is possible to control various elements by means of which dosing and/or process parameters of the ground milling machine are set. Elements that are typically controlled can be, for example, valves, orifice plates, pumps, hydraulic power units, electric motors and/or combustion engines (in particular for adjusting rotational speeds), etc. It is particularly preferred if a dosing system of the ground milling machine is controlled for discharging at least one fluid in Step F). The dosing system refers to the device of the ground milling machine by means of which the type and/or the amount of the discharged fluid can be controlled. To this end, the dosing system usually comprises a system of conduits, valves and corresponding discharge openings. Such discharge openings can be, for example, nozzles, spray bars or the like inside a milling drum space. If foamed bitumen is produced, the dosing system can, for example, also comprise expansion chambers into which compressed air, water and bitumen can be introduced in a controlled manner, as described, e.g., in DE 102010013982 A1. It is then preferred that the mobile unit is configured in such a manner that the process expert can enter and transmit suggested values, e.g., for dosing parameters such as the pressure of the compressed air fed into the expansion chamber, amount of water, amount of bitumen, and percentages (in particular percentage of foamed bitumen, percentage of bitumen and percentage of water) relative to the processed ground volume, etc.

The manner in which the information is transmitted from the mobile unit to the ground milling machine can vary. The mobile unit can, for example, be connected to the ground milling machine via a cable connection for the data transmission, although wireless embodiments are preferred. This can involve, e.g., establishing a radio connection between the mobile unit and the ground milling machine. This can be done using the following technologies: Bluetooth, WLAN, ZigBee, NFC, Wibree, WiMAX, IrDA and optical directional radio communication as well as proprietary radio communication technologies. The ground milling machine comprises a suitable receiving and evaluation unit. The ground milling machine thus particularly preferably comprises a base station configured for establishing a wireless data connection with the mobile unit.

The mobile unit is a terminal device that can be transported separately from the ground milling machine and that can ideally be operated manually. It is possible that the ground milling machine comprises a special-purpose mobile unit for carrying out the method according to the invention. This is a mobile unit that is, at least essentially, provided exclusively for the aforementioned purpose and is, for example, offered in combination with the ground milling machine. Ideally, however, the process expert can use an already existing and/or common mobile unit to enter the suggested values and transmit them to the ground milling machine. This can be in particular a smartphone or a tablet computer with WLAN capability on which corresponding software is installed, e.g., as a so-called app. The software on the mobile unit is compatible with the software of the ground milling machine. The process expert can then install the software, e.g., on his smartphone, so that it is not necessary to acquire a separate mobile unit. It is further also possible that the necessary software (e.g. a web browser) is already present and available for use on the mobile unit, in particular a smartphone or a tablet computer. In this case, the ground milling machine ideally keeps corresponding documents (e.g. a website) ready for display on the mobile unit. The ground milling machine in this case is obviously configured to receive the signals emitted by such a mobile unit, for example, by means of the establishment of a local network and/or the provision of further services (e.g. a web server), etc., as mentioned above.

In order to obtain an unambiguous attribution between the mobile unit and the ground milling machine, the start-up procedure prior to steps A) to F) preferably requires an initial log-in at or coupling of the mobile unit with, e.g., the machine control unit of the ground milling machine. The mobile unit is thus identified at the ground milling machine, which also facilitates, e.g., an authorization check. Additionally or alternatively, in particular an identification of the process expert operating the mobile unit can also occur.

In particular in view of the increasing use of a plurality of transmitters and receivers on construction sites, the method according to the invention further preferably includes a blocking function, which is configured in such a manner that the machine control considers solely those values proposed by a single mobile unit, in particular the logged-in/coupled mobile unit, during operation. In this embodiment of the method according to the invention, there is thus an exclusive (wireless) pairing of a ground milling machine with a single mobile unit for the current working operation. This ensures that the ground milling machine only considers values proposed by a single mobile unit. For safety reasons, e.g. a reconfirmation of the mobile unit can also be required within certain time intervals (e.g. by means of a new registration/coupling or at least an acknowledgment that the connection between the mobile unit and the ground milling machine is still desired). The blocking function prevents the ground milling machine from considering and displaying values suggested by another mobile unit, e.g. another smartphone, to the driver. There is thus always an exclusive and unambiguous matching between the mobile unit and the ground milling machine. Alternatively, however, it is also possible that several mobile units log in at the ground milling machine simultaneously, e.g. for process experts respectively located in front of and behind the ground milling machine in the working direction and/or for an operator of another machine. This way, it is possible to transmit suggested values to the driver in both a proactive and a reactive manner—simultaneously—with respect to the working process.

An essential idea of the invention is that the driver of the ground milling machine essentially remains in control of the operation of the ground milling machine. It is thus preferable that driving parameters can be entered solely by the driver and that the process expert cannot transmit suggested values in this connection but rather only dosing and/or process parameters. The implementation of the suggested values transmitted by the process expert via the mobile unit thus also ideally includes an acceptance or rejection of the at least one suggested value in step E). The acceptance and/or rejection in step E) can occur via a confirmation function, in particular a one-step confirmation function. By means of the confirmation function, the driver of the ground milling machine thus has to actively approve and/or reject the implementation of the at least one suggested value. In practice, such a confirmation function can consist, e.g., in the actuation of a switch, etc. In order to facilitate the ground milling machine driver's job as much as possible, the confirmation function is preferably configured as a so-called one-step confirmation function. This means that the driver is preferably provided with a “Yes”/“No” choice to which he can respond by actuating a single switch. For example, an acceptance of the at least one suggested value occurs if the driver accepts the at least one suggested value within a determined time period, e.g. 1 minute, e.g. by actuating a switch or a button. If this time period elapses, the at least one suggested value is automatically rejected. This process can also be reversed, so that the elapsing of a time period results in automatic implementation, whereas a rejection requires a prompt actuation of a switch.

The method according to the invention can also include an additional option according to which the driver of the ground milling machine optionally switches to an automatic mode, e.g. when he is accompanied by a very experienced process expert. In the automatic mode, the values proposed by the process expert are always implemented automatically and with no further verification by the driver. The driver of the ground milling machine is then completely relieved of entering dosing and/or process parameters during the milling procedure. Provision can also be made for the driver to only allow individual dosing and/or process parameters for the automatic mode, whereas the remaining dosing and/or process parameters can only be altered by means of the transmission of suggested values.

According to another advantageous embodiment of the method according to the invention, an unrestricted adjustment range is provided with respect to at least one dosing and/or process parameter set in step A), within which range the at least one suggested value entered at the mobile unit and transmitted in steps B) and C) is implemented directly by the machine control unit, and the implementation of steps D) to F) is only required if the at least one suggested value is outside the unrestricted adjustment range. This alternative method thus constitutes a compromise between the automatic mode and the general requirement of a confirmation by the driver of the ground milling machine. Within the unrestricted adjustment range, the process expert can thus influence the dosing and/or process parameters directly via the mobile unit. If the process expert deems necessary modifications of the at least one dosing and/or process parameter that go beyond the unrestricted adjustment range, an intervention of the driver of the ground milling machine is required, e.g. by means of a corresponding confirmation. The advantage of this alternative method is that the driver of the ground milling machine essentially remains in control of the process. However, the process expert can optimize the working operation within the unrestricted adjustment range directly, without having to bother the driver of the ground milling machine. The unrestricted adjustment range can be defined to always be a range around a dosing and/or process parameter set at the beginning of the milling operation or a current dosing and/or process parameter. This can thus be a certain plus/minus percentage or absolute value relative to an initial value of a dosing and/or process parameter set at the ground milling machine at the beginning of the working operation, e.g. a maximum of plus/minus 2%, in particular plus/minus 1% and especially plus/minus 0.1%. The unrestricted adjustment range then varies accordingly depending on the dosing and/or process parameter set at the beginning of the milling operation or the current dosing and/or process parameter. Alternatively, however, it is also possible to define the unrestricted adjustment range in a fixed manner, e.g. in such a way that the unrestricted adjustment range of the at least one dosing and/or process parameter, the maximum adjustment range of which lies between 0% and 100%, is always in a certain range, for example 40% to 60%.

The driving and/or the dosing and/or the process parameters are further preferably documented during the milling operation, in particular in a storage device on the side of the machine. Additionally or alternatively, the driving and/or the dosing and/or the process parameters are documented and stored on the mobile unit during the milling operation, in particular in relevant intervals for further processing by the process expert or for billing purposes. The entries of the process expert on the mobile unit are ideally also documented. This way, it is possible to obtain a comprehensive overview of the work performed even after the working operation and in particular to assign responsibilities to the driver and/or the process expert. The method according to the invention can thus also comprise an evaluation step in which the documentation data stored in the storage device are read out and evaluated. This can involve, for example, transmitting the documentation to the mobile unit and/or from the ground milling machine via the Internet to a control center.

To improve the operational safety of the method according to the invention, the method can comprise a protective field function such that a warning signal is triggered when the mobile unit is located within a defined and monitored safety area of the ground milling machine. Such a protective field can be obtained, e.g., via infrared, ultrasonic and/or laser sensors and/or by using RFID technology. However, additionally or alternatively, other suitable technologies can also be used here such as WLAN or Bluetooth. For example, reference is made to US 20130070607 A1 in this regard. The triggering of a warning signal can also occur in different manners. For example, the warning signal can consist in an indicator light and/or an acoustic signal. Additionally or alternatively, however, it is also possible to trigger machine functions such as an emergency stop function by means of the machine control unit.

In addition, in preferred embodiments of the invention, the exchange of information between the mobile unit and the ground milling machine can be optimized even further. For example, it is in particular also possible that image and/or video and/or audio material or data is exchanged between the ground milling machine and the mobile unit in one and/or both directions. This unidirectional or bidirectional data exchange can be used, e.g., to display image data taken by the process expert with the mobile unit, e.g. of the milled track, on a display screen and thus to provide a detailed impression of the current work result to the machine operator. Additionally or alternatively, however, it is also possible that image data taken with a camera arranged on the ground milling machine are sent to the mobile unit for display. This can make sense in particular when the process expert is inspecting the milled material or the milled track behind the ground milling machine and wants to check whether the condition of the ground area in front of the ground milling machine (provided that a corresponding camera is arranged on the ground milling machine) is similar or different. Storage and/or transmission of the aforementioned data, for example via the Internet, to a control center for documentation purposes is further also possible and comprised by the invention.

A further aspect of the invention consists in a ground milling machine, in particular a ground stabilizer and/or recycler, with a mobile unit. Together, the ground milling machine and the mobile unit are particularly preferably configured to carry out the method according to the invention. Generic ground milling machines usually comprise a drive engine, in particular a diesel engine, traveling devices such as wheels and/or crawler tracks, a machine frame, a working drum with a plurality of working tools such as milling tools, mixer bars, etc. arranged on its external surface, a dosing system configured so as to be able to dose a discharge of fluid, in particular into a milling drum space, an operator's cab with operating devices by means of which driving, dosing and/or process parameters can be entered by a driver, a display device inside the operator's cab, e.g. a display screen and/or display instruments via which driving, dosing and/or process parameters can be displayed, and a machine control unit configured so as to transmit control commands corresponding to the driving, dosing and/or process parameters entered by means of the operating devices to the corresponding devices (i.e. those devices that are controlled to implement the control commands in order to obtain the specified driving, dosing and/or process parameters, e.g. electric motors, magnets, pumps, valves, etc.). With regard to the structure and the mode of operation of generic ground milling machines, reference is also made to the statements made above.

According to the invention, a mobile unit comprising at least one input device and a transmitter is provided in addition to the ground milling machine. The mobile unit is configured to be combined with the ground milling machine, which accordingly comprises a receiver via which suggested values sent by the mobile unit can be received and evaluated, e.g. for display to the driver of the ground milling machine. According to the invention, at least one suggested value for at least one of the dosing and/or process parameters can thus be entered and transmitted to the receiver via the mobile unit. The receiver transmits the received suggested values to the machine control unit for display by means of the display devices in the operator's cab of the ground milling machine. Suggested values entered by the process expert via the mobile unit outside the ground milling machine are thus displayed in the operator's cab of the ground milling machine. It is thus possible for the driver to receive information regarding how dosing and/or process parameters can be adjusted for the optimization of the work result from the process expert from outside the ground milling machine. To this end, he does not have to leave the operator's cab or interrupt the milling operation.

An optoelectronically readable code, in particular a barcode or QR code, which encodes a log-in code for the mobile unit at the ground milling machine, is preferably provided on the ground milling machine, in particular on one of its external surfaces, while the mobile unit comprises a reading device for an optoelectronically readable code, in particular a digital camera, and a corresponding evaluation unit. With the aid of the optoelectronically readable code, it is possible to store, e.g., log-in information permitting the establishment of a connection between the mobile unit and the ground milling machine on the external surface of the ground milling machine. Additionally or alternatively, a link for downloading a suitable software to the mobile unit or a link for retrieving a suitable website provided, e.g., by the ground milling machine, etc., can be provided by means of the optoelectronically readable code.

The machine control unit coordinates the interaction between the suggested values received from the mobile unit, the commands entered by the driver in the operator's cab of the ground milling machine and the setting of in particular the dosing and/or process parameters by means of the control of, e.g., suitable actuators such as valves, throttles, pumps, etc. The machine control unit is preferably configured so as to implement the at least one suggested value sent by the mobile unit if the driver in the operator's cab has confirmed the same or a certain time period has elapsed, or vice versa. In the first case, the suggested values from the mobile unit are thus accepted only if the driver of the ground milling machine gives his explicit consent. This input principle can be reversed so that any suggested value is accepted automatically unless the driver of the ground milling machine rejects the suggested value within a predetermined time frame. What is essential here is that there is no direct and immediate implementation of the suggested values. The final decision remains with the driver of the ground milling machine. The confirmation for the acceptance and/or rejection of the suggested value can be carried out in various manners. Preferably, a separate confirmation switch is arranged in the operator's cab for this purpose. When the switch is actuated, confirmation occurs, in particular with respect to the currently displayed suggested value. Such a confirmation switch can be, e.g., a push button or in particular also a suitable display field within a touch-sensitive display screen.

Additionally or alternatively, the machine control unit is preferably configured so as to allow, for at least one dosing and/or process parameter, a direct adjustment of the at least one dosing and/or process parameter within an unrestricted adjustment range. In this embodiment, the process expert is thus permitted a direct influence over, i.e. can directly alter, at least one dosing and/or process parameter within a limited range via the mobile unit. This contributes further to relieving the driver of the ground milling machine during the working operation. The scope of the unrestricted adjustment range can be, for example, predefined ex-works or defined individually. In this regard, reference is made in particular to the description of the method according to the invention.

In order to facilitate orientation for the driver of the ground milling machine, it is preferable to provide a separate display device in the operator's cab of the ground milling machine by means of which the at least one suggested value is displayed, in particular exclusively. It is generally preferable to integrate or display the suggested values transmitted by the process expert via the mobile unit in existing displays, in particular display screens. This, however, requires an increased attention on the part of the driver of the ground milling machine. It can thus also be advantageous if there is a distinct, separate display device for communicating with the process expert, which exclusively displays respective suggested values. This way, the driver of the ground milling machine can see immediately that the displayed information is a suggested value from the process expert which has to be, e.g., confirmed by rejection and/or acceptance.

A further part of the machine control unit is preferably a documentation storage unit for driving, dosing and/or process parameters in order to also have an overview of the working operation of the ground milling machine after completion, e.g. for billing purposes. Here, in particular a storage of the suggested values transmitted by the process expert via the mobile unit and the corresponding responses of the driver of the ground milling machine occurs. The term machine control unit here is to be understood in a generic sense and thus in particular also comprises embodiments in which the control of the machine occurs by means of multiple machine control subunits that can exchange data via suitable communication interfaces (e.g. a CAN bus).

Finally, a further aspect of the invention also consists in a mobile unit for a ground milling machine with a mobile unit, as described above. The mobile unit according to the invention comprises a display device, an input device and a transmitter. By means of the input device, the process expert can enter suggested values from outside the ground milling machine, which are subsequently transmitted via the transmitter of the mobile unit to the receiver of the ground milling machine. According to the invention, the mobile unit is provided with its own control unit, which controls the input device, the display device and the operation of the transmitter. The mobile unit ideally has a touch-sensitive screen and is in particular a smartphone or a tablet PC.

The combination between the mobile unit and the ground milling machine can be realized in various manners, although options that include a wireless connection are generally preferred. In addition, the mobile unit is ideally configured to establish a wireless Internet connection in order to, e.g., facilitate a centralized authorization process, e.g., by means of a control center on the construction site. This can be advantageous in particular when several ground milling machines are being operated on a construction site simultaneously.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in greater detail below with the help of the embodiments indicated in in the figures, which show schematically:

FIG. 1 is a side view of a ground milling machine and a mobile unit;

FIG. 2 is an operation scheme of the embodiment shown in FIG. 1;

FIG. 3 is a flowchart of a method according to the invention; and

FIGS. 4A and 4B are progression curves of a dosing parameter when using the method according to the invention.

DETAILED DESCRIPTION

Identical or functionally similar components are indicated with identical reference numbers, although recurring components are not necessarily indicated separately in each figure.

FIG. 1 illustrates a side view of the general structure of a ground milling machine 1, which in the specific embodiment is a ground stabilizer. Essential elements of the ground milling machine 1 include a machine frame 2, comprising a front frame 2A and a rear frame 2B that are connected with one another via an articulated joint 3, a drive engine 4, an operator's cab 5, traveling devices 6, a milling drum 7, a milling drum hood 8, and a dosing system 9. The dosing system 9 comprises a fluid tank 10, fluid connection lines 11, a pump 12, and a discharge device 13, via which the fluid can be introduced into the interior space enclosed by the hood 8. The fluid can be, e.g., water, bitumen or foamed bitumen. In the latter case, additional lines are provided for the further components for producing foamed bitumen in a manner known per se (bitumen, water and compressed air). The operator's cab 5 is equipped with input devices 15, e.g., levers, switches, touchscreens, by means of which the driving motions of the ground milling machine 1 (driving parameters), the dosing system 9 (dosing parameters) as well as the positioning and the operating mode of the milling drum 7 (process parameters) can be set via a corresponding machine control unit 14. In order to control the dosing parameters, e.g., the machine control unit 14 is connected directly to the pump 12 and the discharge device 13 of the dosing system 9 via connection lines 16 and 17, or it is connected to a control unit 32 of the dosing system 9 (FIG. 2), which in turn controls the individual actuating elements of the dosing system 9. In order to control the driving parameters and the process parameters, the machine control unit is also connected to corresponding control units and/or actuators. Further, a sensor system can be provided by means of which actual values of the driving and/or dosing and/or process parameters are detected and transmitted to the machine control unit 14, which then displays them in the operator's cab 5. To this end, the ground milling machine 1 comprises a display device 18 in the operator's cab 5, which is connected to the machine control unit 14 via a connection line 19. Finally, a receiver 20 is provided which is also connected to the machine control unit 14. The machine control unit 14 can alternatively also consist of several subunits that exchange data via a suitable communication interface, e.g., a CAN bus. The term “machine control unit 14” hereinafter also covers this variant.

Provided outside the ground milling machine 1 is a mobile unit 21 comprising a housing 22, a control unit 23, a transmitter 24 as well as a touch-sensitive display screen 25 by means of which a process expert located next to the ground milling machine 1 can perform manual inputs. To this end, he can use the button 26 to alter, e.g., dosing parameters such as the type of the discharged fluid, the amount of discharged fluid (e.g. per unit of time and/or distance and/or milling volume), etc., and/or use the button 27 to alter process parameters such as the milling drum speed, the milling depth, etc. The button 28 can be used to conduct a log-in of the mobile unit at the ground milling machine at the beginning of the operation, and the button 29 can be used to trigger a transmission via the transmitter 24 to the receiver 20 of the ground milling machine. The mobile unit further comprises a digital camera 51. This can be used, e.g., to read an optoelectronically readable code (QR code 50) that is arranged on the ground milling machine 1 and that encodes log-in information for the registration of the mobile unit at the ground milling machine 1 or, e.g., a web address. The camera can further be used for recording image and/or video material for transmission to the ground milling machine and/or the control center.

FIG. 2 further illustrates the schematic structure of the arrangement of FIG. 1. The contours of the ground milling machine 1 are designated by B. FIG. 2 illustrates the central arrangement of the input devices 15 and the display devices 18 in the operator's cab 5. Also provided is a confirmation switch 30, e.g. a push button, the mode of operation of which is explained in greater detail below. The confirmation switch 30 is connected to the machine control unit 14 via a connection line 31. FIG. 2 in particular also illustrates further details concerning the structure and operating principle of the dosing system 9. In the present embodiment, the dosing system 9 has its own central control unit 32, which is connected to the pump 12, a pressure sensor 33, a stopcock 34 and valves 35 via corresponding signal lines. Coming from the tank, which is not shown in FIG. 2, via the connection line 11, the fluid is thus pumped by the pump 12 into one or both of the spray bars 36, which longitudinally extend parallel to the rotation axis of the milling drum 7 inside the milling drum space covered by the hood. Exiting the line via nozzles distributed along the spray bars 36, the fluid enters the inner space covered by the hood 8 and is admixed to the substrate by the rotating milling drum. It is also possible to configure the spray bars 36 as devices for the production of foamed bitumen in which case, in addition to the line system shown, a supply of bitumen and compressed air as well as corresponding expansion chambers are also provided for the formation of foamed bitumen.

FIG. 2 further illustrates that the mobile unit 21 is operated manually by the process expert outside the ground milling machine 1 and can communicate with the ground milling machine 1 (specifically by means of the receiver 20) by means of the transmitter 24. Depending on the embodiment, the communication connection can also be bidirectional. For example, dosing and/or process parameters detected by means of a sensor system not shown in the figures (e.g., the pressure sensor 33) can also be transmitted simultaneously from the ground milling machine 1 to the mobile unit 21 for display on the mobile unit 21 so that the process expert is also kept up to date regarding the current dosing and/or process parameters.

According to FIG. 2, the ground milling machine 1 further comprises protective field devices 37, e.g. in the form of ultrasonic or infrared sensors. With the aid of the protective field sensors 37, a distance range towards the ground milling machine 1 is monitored. In FIG. 2, said protective field range is designated by S. This ensures that the mobile unit 21 (and thus the process expert) keeps a safe distance from the ground milling machine 1. If the mobile unit 21 moves into the safety range, an (optical and/or acoustic) alarm is triggered in the operator's cab 5 and/or the ground milling machine 1 is stopped automatically or even shut down. Additionally or alternatively, other technologies suitable in this connection, such as WLAN or Bluetooth, can also be used. These two specific variants are advantageous, for example, in that they facilitate a monitoring of this distance without separate sensors.

The interaction between the mobile unit 21 and the ground milling machine 1 is explained in greater detail below with reference to FIG. 3, which further illustrates the sequence of a method according to the invention. What is essential here is that the mobile unit 21 is operated by another person (process expert) next to the driver of the ground milling machine 1 located in the operator's cab 5. The process expert can remain in the vicinity of the ground milling machine 1 during operation of the ground milling machine 1 and can, for example, check the quality of the work result in the working direction A behind the ground milling machine 1. Via the mobile unit 21, he can propose at least one suggested value of a dosing and/or process parameter to the driver of the ground milling machine 1 if the current work result of the ground milling machine 1 is not satisfactory. This can occur, for example, if the characteristics of the ground change in the course of the milling procedure. According to the method, the milling procedure is thus initially started in step 38 by the driver of the ground milling machine 1 by means of the setting of driving, dosing and/or process parameters. As the milling procedure continues, the process expert can inspect the work result. In step 39, he can use the mobile unit 21 to enter at least one suggested (absolute or relative) value for at least one dosing and/or process parameter in order to further optimize the work result, e.g. he can propose an increase in the amount of fluid dispensed by the dosing system 9. Once entered, the at least one suggested value can be transferred to the ground milling machine (transmitter-receiver) in step 40. Step 41 now involves displaying the at least one suggested value to the driver of the ground milling machine in the operator's cab by means of the display device 18. The driver thus now has the possibility to take note of the suggested value, i.e. the modification proposed by the process expert. In step 42, the driver now has to decide whether to reject (43) or to accept (44) the at least one suggested value. If he accepts the suggested value, e.g. by actuating a suitable input means such as a switch, the machine control unit sends, in step 45, a corresponding control command to, e.g., the dosing system for the modification of an actual value of the at least one dosing and/or process parameter towards the at least one accepted suggested value of the at least one dosing and/or process parameter. The ground milling machine 1 is thus preferably also equipped with a suitable sensor system, by means of which the actual value of the at least one respective dosing and/or process parameter is monitored and transmitted to the machine control unit. In practice, the control of the dosing system of the ground milling machine has proven particularly advantageous. The method described above is thus used in particular to alter, e.g., the amount of fluid applied via the dosing system, e.g. water. According to this method, the final decision whether or not the value proposed by the process expert is actually implemented in the current working operation thus ultimately remains with the driver of the ground milling machine.

Provision can specifically be made in this regard for the driver of the ground milling machine to trigger the decision for the implementation of the suggested value in the manner described above by means of a confirmation function according to step 46. The confirmation function according to step 46 can be designed in such a manner that the driver of the ground milling machine gives his consent to the implementation of the suggested value by actuating a confirmation means. If confirmation is not given within a predetermined time frame, the suggested value is automatically rejected. Such a time frame can be in the order of, for example, 1 minute. Alternatively, the driver can reject the suggested value by means of an active confirmation, or the design can be such that the driver has to either actively accept or reject the suggested value. Either way, it is preferred that the driver merely has to perform a single switch actuation (one-step confirmation function).

An advantageous embodiment of the method according to the invention can consist in particular in displaying, in step 52, the current driving and/or dosing and/or process parameters on the mobile unit 21 (i.e. the parameters are first detected on the ground milling machine, before they are sent to the mobile unit, where they are finally displayed). In this manner, the process expert gains a deeper insight into the current milling procedure and, in addition, can more easily determine absolute suggested values for his suggested values for the dosing and/or process parameters. Specifically, the display can occur via the display screen 25 of the mobile unit 21.

According to a further option, the method according to the invention further makes it possible for the entries of the process expert via the mobile unit to be implemented at the ground milling machine within a defined adjustment range directly following step 40. In this case, the machine control unit checks in step 47 whether the suggested value is within the adjustment range for the dosing and/or process parameter in question. If this is the case, the machine control unit directly triggers an alteration of the actual value towards the suggested value, so that no active intervention of the driver of the ground milling machine is required for implementation in this case. The mobile unit thus constitutes a kind of remote control for this adjustment range. However, if the suggested value is outside the adjustment range, the scheme described above, including the requirement of a decision by the driver of the ground milling machine, is run.

All actions described above are preferably documented in a further step 48. This is preferably also where an attribution of the decisions of the process expert and the driver of the ground milling machine occurs for subsequent transparency. For example, a corresponding storage device in which the respective data are stored can be provided on the ground milling machine for documentation purposes. Moreover, the stored data can be transmitted, e.g. via the Internet, to a control center such as the management of the construction site.

In case multiple and/or conventional devices are used as mobile units simultaneously, it is further preferred that a log-in/coupling of the mobile unit at the ground milling machine is required in step 50, i.e. prior to the working operation. This way, the mobile unit is identified at the ground milling machine. At the same time, it is possible to ensure, with the aid of a blocking function, that only values proposed via the currently logged-in mobile unit are transferred to and considered by the ground milling machine for the current working operation. This results in an unambiguous matching.

FIGS. 4A and 4B illustrate the method based on the progression of an illustrative parameter, in this case the water discharge volume M of the dosing system 9 per time unit. At the time to, a regular ground processing operation is begun during which a certain amount M1 of water per time unit is dispensed via the dosing system into the inner space formed by the hood and surrounding the milling drum. At the time t1, the process expert entered a suggested value M2 into the mobile unit and transmitted it to the ground milling machine. This is now displayed to the driver of the ground milling machine. At the time t2, the driver of the ground milling machine decides to accept the suggested value. The actual value 49 is now accordingly modified until, at the time t3, it corresponds to the suggested value accepted by the driver.

FIG. 4B, in contrast, illustrates the situation when the suggested value is within an unrestricted adjustment range VB. Here again, at the time t1, the process expert provides a suggested value M2, which is transmitted to the ground milling machine. The machine control unit determines that the suggested value M2 is within the adjustment range VB so that the actual value 49 is, without any intervention on the part of the driver of the ground milling machine, directly adjusted towards the suggested value, which is reached at the time t2. At the time t3, the process expert transmits another suggested value of M3. Said value is outside the adjustment range VB so that the machine control unit does not initiate a direct implementation of the suggested value. The suggested value is instead displayed to the driver of the ground milling machine, who in the present case approves the suggested value at the time t4, so that an adjustment of the actual value, which in the present case is completed at the time t5, is performed only afterwards. 

What is claimed is:
 1. A method for operating a ground milling machine, comprising a ground stabilizer and/or a recycler, the method comprising the steps of: A) conducting a milling operation on a substrate by setting of at least one of at least one driving parameter, at least one dosing parameter or at least one process parameter; B) entering at least one suggested value for the at least one dosing parameter and/or the at least one process parameter via a mobile unit; C) sending the at least one suggested value to the ground milling machine; D) displaying the at least one suggested value by a display device in an operator's cab of the ground milling machine; E) accepting the at least one suggested value, or rejecting the at least one suggested value; and F) if the at least one suggested value is accepted, sending, by a machine control unit, a corresponding control command for a modification of an actual value of the at least one dosing parameter and/or a modification of an actual value of the at least one process parameter towards the at least one accepted suggested value of the at least one dosing parameter and/or the at least one process parameter, respectively.
 2. The method according to claim 1, further comprising displaying the actual value of the at least one dosing parameter on the mobile unit and/or the actual value of the at least one process parameter on the mobile unit and/or an actual value of the at least one driving parameter on the mobile unit.
 3. The method according to claim 1, wherein step F) involves controlling a dosing system of the ground milling machine for a discharge of at least one fluid.
 4. The method according to claim 1, wherein step A) to step F) are preceded registering the mobile unit at the machine control unit of the ground milling machine.
 5. The method according to claim 1, further comprising operating the machine control unit such that the ground milling machine exclusively considers the at least one suggested value from the mobile unit to an exclusion of another mobile unit.
 6. The method according to claim 1, wherein the acceptance and/or rejection in step E) is performed by a one-step confirmation function.
 7. The method according to claim 1, wherein an unrestricted adjustment range is provided with respect to the at least one dosing parameter and/or the at least one process parameter set in step A), within which range the at least one suggested value that has been entered at the mobile unit and transmitted in step B) and step C) is implemented directly by the machine control unit, and the implementation of step D) to step F) is only required if the at least one suggested value is outside the unrestricted adjustment range.
 8. The method according to claim 1, wherein documentation of at least one of the at least one driving parameter, the at least one dosing parameter or the at least one process parameter is created during the milling operation and stored on the ground milling machine.
 9. The method according to claim 1, wherein a protective field function is provided such that a warning signal is triggered when the mobile unit is located within a defined and monitored safety range.
 10. A ground milling machine, comprising a ground stabilizer and/or a recycler, with a mobile unit, comprising: a drive engine; traveling devices; a machine frame; a working drum with a plurality of working tools arranged on an external surface of the working drum; a dosing system configured to be usable to dose a discharge of a fluid; an operator's platform with operating devices, wherein at least one of at least one driving parameter, at least one dosing parameter or at least one process parameter is enterable by a driver; a display device inside an operator's cab, wherein the at least one of the at least one driving parameter, the at least one dosing parameter or the at least one process parameter is displayable; and a machine control unit, configured to transmit control commands corresponding to the at least one of the at least one driving parameter, the at least one dosing parameter or the at least one process parameter set by the operating devices to corresponding devices, wherein the mobile unit comprises at least one input device and a transmitter, wherein a receiver configured to receive signals sent by the transmitter is arranged on the ground milling machine, wherein at least one suggested value for at least one of the at least one dosing parameter and/or the at least one process parameter is enterable via the mobile unit and transmitted to the receiver, and wherein the receiver transmits the at least one suggested value to the machine control unit to display via the display device.
 11. The ground milling machine with a mobile unit according to claim 10, wherein an optoelectronically readable code, which encodes a log-in code for the mobile unit at the ground milling machine, is provided on the ground milling machine, and wherein the mobile unit comprises a reading device to read the optoelectronically readable code.
 12. The ground milling machine with a mobile unit according to claim 10, wherein the machine control unit is configured to implement the at least one suggested value sent by the mobile unit when the at least one suggested valve has been confirmed.
 13. The ground milling machine with a mobile unit according to claim 10, wherein a confirmation switch, by an actuation of which a confirmation is entered, with respect to the at least one suggested value, is arranged in the operator's cab.
 14. The ground milling machine with a mobile unit according to claim 10, wherein the machine control unit is configured to allow, for at least one of the at least one dosing parameter and/or the at least one process parameter, a direct adjustment of the at least one dosing parameter and/or the at least one process parameter within an unrestricted adjustment range (VB).
 15. The ground milling machine with a mobile unit according to claim 10, wherein a separate display device is provided in the operator's cab of the ground milling machine, via which the at least one suggested value is displayed exclusively.
 16. The ground milling machine with a mobile unit according to claim 10, wherein the machine control unit has a documentation storage unit for at least one of the at least one driving, parameter, the at least one dosing or the at least one process parameter.
 17. The ground milling machine with a mobile unit according to claim 10, wherein the mobile unit comprises a display device, an input device and a transmitter, wherein the mobile unit has a control unit by which the at least one suggested value entered for the at least one dosing parameter and/or the at least one process parameter is transmittable via the transmitter to the ground milling machine.
 18. The ground milling machine with a mobile unit according to claim 17, wherein the mobile unit has a touch-sensitive screen.
 19. The ground milling machine with a mobile unit according to claim 17, wherein the mobile unit is configured to establish a wireless connection to a network. 